1. Field of the Invention
This invention relates in general to respiratory therapy devices and, in particular, to a continuous positive airway pressure therapy device which maintains continuous positive pressure to a patient's lungs through the use of a flow amplifier for maintaining the positive pressure during a patient's inspiration, breath pause and expiration portions of the breathing cycle.
More specifically, but without restriction to the particular embodiment and/or use which is shown and described herein for purposes of illustration, this invention relates to a continuous positive airway pressure therapy device having a flow amplifying body and which is adapted for connection to a source of compressed air or oxygen to generate a positive airway pressure during inhalation, breath pause and exhalation.
2. Description of Related Art
Devices for maintaining or inducing a constant positive pressure within the airway passages of a patient are generally incorporated into breathing machine systems such as an anesthesia machine or respirators. Accordingly, such equipment is complicated, moderately cumbersome and expensive. While continuous positive airway pressure has been utilized for many forms of respiratory therapy, such as the treatment of pulmonary edema (cardiogenic and noncardiogenic), acute hypoaxaemic respiratory failure, thoracic trauma, asthma, chronic obstructive airway disease, pneumonitides, atelectasis and sleep apnoea, the availability of a simple, inexpensive and reliable continuous flow device would increase the therapeutic modality of this form of therapy. It would, therefore, be desirable to have such a continuous positive airway pressure device which would be capable of delivering a positive pressure to a patient's respiratory system throughout the patient's inspiratory and expiratory cycle, while minimizing the work of breathing created by the device.
The present invention provides such a device with the use of a nominal compressed gas source by utilizing a Coanda profile and an internal orifice to create a high velocity turbulent flow from the compressed gas source that effectively entrains ambient air flowing towards the patient thereby creating a positive airway pressure. This positive airway pressure amplifies the flow of ambient air to a patient during inhalation, maintains the positive pressure during breath pause while the flow of compressed gas is no longer directed towards the patient, and, upon expiration, the compressed gas flow is overcome by the patient's expiratory air flow while still providing positive airway pressure.